The Nexus 10 I had started slowing down as well. I wiped it, but I think if I had let it get this OTA I would've seen performance improve as a result, since I filled that device with videos and deleted them to add more quite often (great for watching stuff on a plane).

Now you are making me NOT want to sell mine. I picked up the new N7 for portability (I had the old one and used it much more than my N10) and was planning to sell mine to pick up the cost of the new one. Reply

They also seem to have done something to improve graphics acceleration in chrome and in the launcher even more. That's my first perception upon installing the update on my Nexus 10. It really feels like a high-end device now.Reply

I'm very curious to try this on my galaxy nexus. I've done a lot of adding and deleting datasheets and cad drawings to it and its started to slow down considerably in the last 6 months. Have any recommendations for a benchmark to run before and after the upgrade to 4.3 to test for improvement?Reply

The fstrim command itself however is not there. I wonder if this new scheduled fstrim functionality calls directly fstrim, or if it re-implements it with system calls. If the former is true then I don't see how it is supposed to work on a gnex that lacks the fstrim executable...Reply

Well, now I know why fstrim is not invoked: because of the daydream (clock) that is running while the phone is charging in the dock. This night I connected the charger directly to the phone and this morning I found the fstrim references in logcat.Reply

I wonder if this will be any different from what lagfix already does, apart from being automatic. Lagfix just runs fstrim on pre 4.3, should have the same effect I guess. Its interesting android never had it before, what about other mobile operating systems? Some sure seem to keep their feet longer.Reply

Amazing! How is this possible at all? I wonder who is designing these technologies and why is this not available by default? Why so many computer technologies are release only half finished? It would be like a car that cannot turn left and the designer: "Go on, will patch it up, when you need to steer."Reply

My 16 GB Nexus 7, picked up on launch day last year, was slowly getting more and more frustrating to use. It hadn't hit the point many people had described in terms of complete unusability, but it certainly was worse than when I had first taken it out of the box... now, two days after updating to 4.3, the thing is as fast as it ever was.

I'm sort of confused why they hadn't added this to the operating system ages ago, but it's great to see it here now, and it's great to see the huge improvements!Reply

TRIM support was ostensibly added to Nexus 7 versions of Android back in 4.1.2, and while it made a difference, performance is still very much sub-optimal. The 4.3 update isn't going to change your current Nexus 7's performance.Reply

The vast majority of comments and Brian's testing above say the exact opposite: that the 4.3 update does indeed convert an unusably slow tablet into an extremely fast one. A D6A also says, it's likely that fstrim as a command was included in the code for 4.1.2, but it wasn't active. I don't think the criteria for activation (80%+, hour-plus deadtime) is aggressive enough and I would rather it attempt an fstrim on upgrade - like Android says, "Upgrading apps ..." - but that it's active rather than just present is a good step in the right direction.Reply

If you look at a pre-4.3 nexus device (perhaps 4.1.2 through 4.2.2), you'll notice that the writeable filesystems (i.e. /data and /cache) are mounted with the "discard" option. This means that the storage is trimmed after EVERY file delete operation. This prevents performance degradation over the long term, but the trade-off is that trimming on-the-fly can effect responsiveness.

4.3 no longer mounts filesystems with "discard" and instead runs TRIM on a schedule when the device is not being used. This has the benefit of preventing performance degradation over the long term, as well as not impacting responsiveness when the device is in use.

I suppose you could still run into temporary problems with this strategy if you were to fill up the entire filesystem with files followed by deleting them, all within a 24 hour period, before the storage has a chance to be trimmed. However, this is an unlikely scenario.Reply

Go to apps, and find the google services framework service. stop the service and wipe the data. Go back to about this tablet and try to upgrade (it should read last upgrade sometime in 1969). It may take 2 or 3 tries but eventually you will upgradeReply

I don't know if they do TRIM specifically, but they definitely don't have the same sort of slow down problems the N7 had. I routine fill up iOS devices to the limit and don't have any kind of slow down at all.Reply

Sounds like a good step in the right direction. Explains a lot of anecdotal observations about devices slowing with age.

Does anyone know where or how to find out which eMMC controllers are found in a device and more importantly which controllers support TRIM? I think it'd be unfortunate if lots of recent devices don't support TRIM. Could be scandalous.@ Brian Klug: TRIM-gate?Reply

My wife was just complaining about how her Droid Razr was running really slow, and it never occurred to me (while it should have) to wonder about trim on the phones. Makes sense as to why they would slow down over time.Reply

My Galaxy S4 GPe is now continually experiencing lag after being used for about a day. Rebooting my phone fixes the issue, but it's incredibly annoying. My home screen suffers from the most lag—kind of has a ghosting effect when I scroll. Other elements—e.g. keyboard—seem to work better, but not as well as they should. I don't know if this is unique to my phone or some sort of software screw up. Anyone else experiencing this issue? I can’t help but think it’s related to the slow storage I/O performance described in this article. My Galaxy Nexus and Nexus 10 never had this problem.Reply

I updated my Gnex last night and I have to say I'm absolutely loving 4.3. I had been experiencing horrible lag and slowdown with my gnex and after the update its almost running like new again. Not only that, but I'm noting an improvement on battery life as well. Reply

"Android 4.3 Fixes First-Gen Nexus 7 Slowdown Issue", "Google Android 4.3 to the Rescue for Old & Laggy Nexus 7", "Android 4.3 may breathe new life in your bogged down Nexus 7", blah-blah-blah... First of all, why just Nexus 7? Buggy eMMC V3U00M is in many devices - HTC One X, SGS3, my Galaxy Nexus and maybe in others. Another question, why we should be very happy with our buggy devices after 4.3 update? TRIM doesn't help get rid of lags and slowdowns, when there's less than 3 GB free memory. With less than 1GB of free space available my GNex slow as hell, and TRIMing and DISCARDing doesn't help at all. And what a strange schedule for automatic "idle maintenance"? When should I charge my phone and let it idle for maintenance start? I've charged it every night for a week, and it never started "idle maintenance", because I haven't seen any trims in logcat and any speed improvements in androbench. And is there any way to force that fstrim process manually without root and lagfix app in 4.3?I don't think that "quietly added TRIM support" in 4.3 is cure-all for devices with eMMC V3U00M.Reply